Thanks for your response. I'm not quite sure what to do, though. I have the following code to use my session object:
require_once $_SERVER['DOCUMENT_ROOT'].'/library/mysession.php';
$obj_mysession = new MySession();
session_start();

What exactly should I then add to the config.php?

Additional note: when I try to open the file/imagemanager the popup 'hangs' on:
http://www.mysite.com/js/tinymce/jscripts/tiny_mce/plugins/imagemanager/index.php?type=im&page=index.html

TIA for any help.

In the class constructor of my session object I've placed the following code:

// Register this object as the session handler
session_set_save_handler( 
    array( &$this, "sess_open" ), 
    array( &$this, "sess_close" ),
    array( &$this, "sess_read" ),
    array( &$this, "sess_write"),
    array( &$this, "sess_destroy"),
    array( &$this, "sess_gc" )
);

As far as I know this causes my object logic to replace the built in session logic in PHP and enables me to save the session data in a database.

I just don't get why the use of my own class causes the hangup on showing the files in the image/filemanager. When I add a print_r( $_SESSION ) in http://www.mysite.com/js/tinymce/jscrip … /index.php it shows the correct session variables.

Hmm, my session object does return some data, namely the data stored in the database for the specified session (which seems logical). It's too bad TinyMCE and my session object don't play nicely. I've now added a redirect to my login procedure to set the TinyMCE session information without using my session object. Not ideal, but it's working now. Thanks for trying to help.